ap•proxi•mantBrE /əˈprɒksɪmənt/NAmE /əˈprɑːksɪmənt/noun 1 (phonetics) a speech sound made by bringing the parts of the mouth that produce speech close together but not actually touching, for example /r/ and /w/ in right and wet in many accents of English 2 (mathematics) a solution that is close to, but not exactly, the solution of a problem